package ch2;

import java.util.Scanner;

public class Ex15 {
    public static void main(String[] args){
        Scanner n = new Scanner(System.in);
        System.out.println("x点：");
        double x1 = n.nextDouble();
        double x2 = n.nextDouble();
        System.out.println("y点：");
        double y1 = n.nextDouble();
        double y2 = n.nextDouble();
        double distance = Math.pow(Math.pow(x2 - x1, 2) + Math.pow(y2 - y1, 2), 0.5);
        System.out.println(distance);
    }
}
